@manual{zend,
    title        = "Zend Framework Reference Guide",
    organization = "Zend Technologies",
    year         = "2011",
    key          = "Zend Framework",
}
@manual{wanderson,
    title = "Site Pessoal",
    author = "Wanderson Henrique Camargo Rosa",
    year = "2011",
    note = "Disponível em http://goo.gl/6Xvda"
}